This invention relates to object recognition systems; and more particularly, it relates to apparatus for positioning a camera within an object recognition system.
One particular use for the present invention occurs in object recognition systems which either grant or deny a person access to a secure area based on whether or not an image from a camera of the person's face is recognized by the system. Also, the present invention can be used in object recognition systems which employ a robotic arm to select or reject a component based on whether or not an image from a camera of the component is recognized by the system.
In all of the above applications, a key task which needs to be performed as part of the recognition process is that two images must be correlated. One of these images is the image from a camera of an unknown object which the system is trying to recognize, and the other image is of a known object which is stored in the system as a reference. If the correlation between the two images exceeds a predetermined threshold value, then the unknown object is recognized.
However before the two images are correlated, it is desirable to position the camera in the object recognition system such that it is closely aligned with the unknown object. Otherwise, if the camera is misaligned, a pixel-by-pixel correlation of the image from the camera and the stored image will be degraded, and that will cause recognition errors.
Also, in the above applications, another task which is desirable to perform is to somehow protect the camera lens from damage. This protection can be achieved by covering the external surface of the lens with a shutter; however, the addition of such a shutter increases the cost of the object recognition system.
Further in the above applications, it often is necessary to provide a means for calibrating the camera. For example, an infrared camera has hundreds of individual pixel sensors which must be periodically calibrated in order for them to generate the same pixel values for an object of uniform temperature. This calibrating means can be provided by a mechanism which periodically moves a planar surface of uniform temperature in front of the lens. However, the addition of such a mechanism will further increase the cost of the object recognition system.
Accordingly, a primary object of the present invention is to provide an object recognition system with a novel camera positioning apparatus which performs all of the above tasks.